Circuit interrupter



March 1931- o. c. TRAVER CIRCUIT INTERRUPTER Original Filed July 12,; 1926 His AfTorne Patented Mar. 10, 1931 UNITED STATES PATENT OFFICE OLIVER C. TBAVE R, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK CIRCUIT INTERRUP'IER Application filed July 12, 1926, Serial No. 121,893. Renewed August 7, 1930.

' This invention relates to circuit interrupters, particularly those having magnetic blowouts for extinguishing the are produced upon interruption of the circuit, and the prin- 5 cipal object of the invention is to provide an improved form of magnetic arc blowout capable of successfully interrupting high voltage power circuits.

In high voltage power circuits, particularly where a relatively large amount of energy is involved, switches of the oil break type ordinarily are employed for switching service, as well as for protecting the circuits against excessive currents. The oil break type of switch, however, is bulky and costly, and has inherent complications, all of which leave much to be desired in the way of a more simple, compact, and less expensive form of high voltage power circuit interrupter. While it has been proposed heretofore to employ in such service switches of the air break type provided with a magnetic blowout for dissipating the arc of the switch, the difficulty of providing a practical and satisfactory form of high voltage power are magnetic blowout has restricted the general use of magnetic blowout air break switches to circuits of relatively low voltage and power. However, with a magnetic arc blowout embodying the improvements of my present invention the various practical advantages of an air break switch may be obtained in high voltage power service. In accordance with my present invention, the magnetic arc blowout is arranged to receive the are from the air break switch and to quickly extend or stretch the arc to a relatively great length and at the same time decrease the energy in the arc to complete the interruption of the circuit. Furthermore, the high voltage are is confined and directed along a definite path. This is accomplished in the preferred form of the invention by providing a series of interconnected blowout coils so mounted in an arc chute of arc-resisting material and connected that the end of the arc is receivedsuccessively by the blowout coils and the coils are successively included in the arc circuit. In this way, one end, or preferably both ends of the are, are moved rapidly along a substantially continuous conducting member in order to extend or stretch the arc and at the same time a progressively increasing amount of reactance of the coils is inserted in the arc circuit so that the current, and consequently the energy, in the arc is decreased until the arc finally breaks and the circuit is interrupted. Preferably, the series of blowout coils is arranged so that of the successive coils in the series, each has a progressively increasing reactance, thus readily permitting a heavy arc current to flow when the end of the are is initially received by the series of coils and progressively reducing the value of the-current in the are as the increasing reactance of the successive coils is included in the arc circuit. Also, the arrangement is such that as the arc passes along the successive blowout coils a restricted blowout path 18 provided for the auxiliary arcs drawn between the adjacent coils.

The accompanying drawing shows a circuit interrupter provided with a magnetic arc blowout embodying a preferred form of the invention. Fig. 1 is an elevation of the circuit interrupter with a portion of the magnetic arc blowout broken away to more fully reveal the interior construction thereof; Fig.

2 is a view schematically showing the path along which the arc is driven and dissipated with my improved form of magnetic blowout and Fig. 8 is a sectional view of the magnetic arc blowout shown in Fig. 1 looking in the direction of the arrows along the line 3-3 and illustrating the details of construction of the blowout.

In Fig. 1 a suitable high voltage circuit interrupter 10, having the main switch element 11 and the arcing switch element 12, is provided with a magnetic arc blowout 13 constructed in accordance with my present invention. The magnetic arc blowout 13 as shown comprises two restricted arc chutes 14 and 15, within which the series of interconnected blowout coils 16 and 17 are mounted in spaced relation to form substantially continuous arcing terminals for' receiving and attenuating the arc from the switch. The arc chutes 14 and 15 preferably are slightly separated, as shown, in order to in terrupt the leakage path between the two series of coils forming the arcing terminals. The switch 10 controls the continuity of the high voltage power circuit represented by the conductors L1 and L2 and the series of interconnected blowout coils 16 is electricallyconnected at one end with the line conductor L1 while the series of blowout coils 1 17 is interconnected in a similar way with the line conductor L2, as indicated in Fig. 2. Preferably the separate blowout coils in each series are spirally wound with a progressively increasing number of turns in the successive coils in the series, as illustrated diagrammatically in Fig. 2. Each of the coils is provide with an arcing terminal 18, 18 18 ,v which preferably substantially surrounds the coil and is connected to the outer turn thereof and also to the inner turn of the next adjacent coil, as shown in Fig. 2.

Fi 3 illustrates in detail the manner in whic the blowout coils are spaced apart and mounted between the arc-resisting members or plates 19 and 20 forming the restricted arc chute 15, as well as the manner in which the successive blowout coils are interconnected. It will be observed that the arcing terminals 18 and 18 cooperate with the arc chute members 19 and 20 to substantially from the path of the main arc A as shown in Fig. 2.

In order to increase the efiectiveness of the series of blowout coils, in supplying a flux transverse the path of the main arc A each coil is provided with a core of magnetic material 22 extending through the center of the coil and insulated therefrom by a suitable insulating bushing 23. The ends of the magnetic core 22 extend be 0nd the arc chute members 19 and 20 an are provided at one end with a flux-distributing plate 24 and at the other end with a flux-distributing plate 25. The barriers 26 and 27 are interposed between the flux-distributing plates 24: and 25 and the arc chute members 19 and 20 in order more efi'ectively to insulate and protect the plates from the arc circuit. The

barrier 27 also serves to insulatethe magnetic flux-distributing plates from the interconnections between the successive coils in the series. These interconnections may, if desired, be located on opposite sides of the coils to further decrease the liability of arc between the coil connectors in extremely high voltage service.

he operation of my improved magnetic blowout in attenuating and dissipatin the arc received from the air break switc 10, thereby effecting the interruption of the circuit, is as follows: When the switch 10 is operated to the open position, as shown in Fig. 2, the main contact 11 first disengages the cooperating. stationary contact 11 there by causing the current in the circuit line conductors L1, L2 to flow through the first blowout coil in the left hand series of coils 16 and thence through the arcing switch member 12. As the arcing switch member 12 is separated from the arcing terminal of the first blowout coilin the series of coils 16, an arc is drawn. As the arcing switch member 12 swings into proximity to the arcing terminal 12 of the first coil of the series of coils 17, the .arc is transferred from the switch member to the arcin terminal of the first coil in the series of coiIs 17. In this way the arc is received by the magnetic blowout from the switch 10 and the first blowout coil in each of the series of blowout coils 16 and 17 is connected in the arc circuit to be enerp" l by the current flowing in the arc. Sf first coil in each of the series of blowout coils is wound with a relatively small number of the turns, the reactance of the coil is of a correspondingly low value. This permits the coils to be energized with even a very heavy current in the arc circuit without causing an excessive voltage drop across the coils. This insures that the arc isreadily received from the switch 10 by the initial coil in each of the arc chutes.

The flow of the current in the are through the initial coils of each of the arc chutes sets up a flux in the magnetic core with which each coil is provided and this flux is distributed by the corresponding arc plates with which the coil is provided transversely to the path of the are between the terminals of the coils.

Furthermore, the coils are so wound that the flux is in such a direction that the reaction of the flux upon the arc drives the end of the are from the initial coil to the next adjacent coil in the series. The auxiliary are formed between the arcing terminals of the adjacent coils is quickly extinguished by the blowout action of the flux in the initial coil in the restrictedblowout path formed between the coils and the cooperating members 19 and 20 of the arc chute. As the end of the arc is received by the next adjacent coil, the latter coil then is energized by the current in the arc and functions in substantially the same manner as the initial coil to drive the end of the are to the next succeeding coil'in the series. In this way, the arc is rapidly extended or stretched to a relatively great length along the substantially continuous conducting path formed by the arcing terminals of the successive coils in the series. At the same time, the increasing reactance of the successive coils serves to reduce the value of the current in the arc and thus, by both extending the arc and reducing the energy therein, the arc is entirely dissipated to thereby interrupt even a high voltage power circuit.

By increasing the number of coils in the series, as well as the insulating and are-resisting properties of the arc chute, my improved form of magnetic arc blowoutmay be applied to interrupt successfully the power circuits of exceedingly high voltage, such as are commonly encountered in transmission line service. Furthermore, my improved magnetic blowout may be applied to receive the are from various forms of air break switches or high voltage overload fuses with equally efficient results. Also, while I have illustrated and described the magnetic arc blowout as formed of two diverging series of coils, it will be apparent that satisfactory resultsmay be obtained from a single series of coils such as employed in each of the arc chutes illustrated with a suitably designed air break switch.

While I have, in accordance with the provisions of the patent statutes, described and illustrated the principle of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof, I desire to have it understood that the apparatus shown is only illustrative, and that the invention may be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A magnetic blowout for interrupting an electric circuit comprising a series of spaced apart blowout coils of progressively increasing reactance arranged to be successively included in circuit with the arc stream as the arc lengthens.

2. A magnetic blowout for interrupting an electric circuit comprising a series of blowout coils of progressively increasing reactanee, each of said coils having an arcing terminal connected thereto, the said arcing terminals being spaced apart along the path taken by the are as the arc lengthens so as to successively include the said coils in circuit with the arc stream.

3. A magnetic are blowout for interrupting an electric circuit comprising a plurality of interconnected blowout coils, and means for supporting the coils in spaced relation in the path of the arc to successively receive the end of the arc and provide a restricted blowout path for the are between the adjacent coils.

4. A magnetic arc blowout for interrupting an electric circuit comprising a series of interconneeted blowout coils disposed in spaced relation and each arranged to. set up a magnetic filed transverse the path of the arc and provided with an arcing terminal for receivand a separate arcing terminal surrounding each coil and electrically connected to one end thereof and arranged to provide a substantially continuous conducting path for one end of the main arc in said chute and define a blowout path for the auxiliary are between ,the coils.

6. A magnetic arc blowout for interrupting electric circuits comprislng an arc chute .formed of arc-resisting members spaced apart in substantially parallel relation to provide a restricted path for the are, a plurality of interconnected spirally-wound blowout coils mounted in spaced relation between said members, aseparate arcing terminal for each coil electrically connected to the outer turn thereof and substantially surrounding the coil and cooperating with said are chute members to enclose the coil and provide a restricted blowout path for the are between the coils.

7. A magnetic arc blowout for interrupting electric circuits comprising an arc chute, a series of blowout coils mounted in said are chute with the coils spaced apart along the path of the arc, a separate arcing terminal for each coil, and connections extending outside of said are chute between the arcing terminal of each coil and the adjacent coil.

8. A magnetic arc blowout for interrupting electric circuits comprising a restricted arc chute formed of arc-resisting members disposed in opposing spaced relation, a series of blowout coils interposed between said members and spaced apart and each having a sep arate arcing terminal to receive the are from the adjacent coil and another terminal, and electrical connections extending outside of said are chute between the arcing terminal of each coil and the said other terminal of the adjacent coil.

9. A magnetic arc blowout for interrupting electric circuits comprising an arc chute formed of arc-resisting members spaced apart in parallel relation, a series of interconnected blowout coils supported between said members with a restricted arc blowout space between the coils, a magnetic core for each blowout coil extending throughsaid arc-resisting members and having a flux-distribution plate at each end thereof on the exterior of the arc chute.

10. A magnetic arc blowout for interrupting electric circuits comprising a series of interconnected spirall wound blowout coils for supplying blowout ux transverse of the arc, and means for supporting the coils in spaced relation in the path of the arc to successively receive the end thereof and thereby insert a progressively increasing reactance in the arc circuit.

11. A magnetic arc blowout for interrupting electric circuits comprising a series of interconnected spirally wound blowout coils for supplyingblowout flux transverse the path of the arc andhaving an increasing number of turns in the successive coils in the series, and means for supporting the .coils in spaced relation to successively receive the end of the arc and thereby insert a progressively increasing re'actance in the arc circuit.

12. A magnetic arc blowout for interrupting electric circuits comprising an arc chute of arc-resisting material, a series of interconnected blowout coils mounted in said are chute in spaced relation in the path of the arc to be successively connected in the arc circuit and having a progressively increasing num-' ber of turns in the successive coils of the series. I

13. A magnetic arc blowout for interrupt ing electric circuits comprising an arc chute formed of arc resisting members disposed in substantially parallel spaced relation, a series of spirally-wound blowout coils mounted between said members with the coils spaced apart and each provided with an arcing terminal cooperating with the arc chute members to enclose the coil, connections between the arcing terminal of each coil and the adjacent coil insulated from the arc in the arc chute, and a magnetic core for each blowout coil extending through said are chute members and having a flux distribution plate on each end thereof on the exterior of the arc chute. i

14. A magnetic arc blowout for interrupts ing electric circuits comprising an arc chute formed of arc-resisting members spaced apart in substantially parallel relation to provide a restricted path for the arc, a series of interconnected blowout coils mounted between said are chute members with a space between the coilsand each having an arcing terminal substantially surrounding the coi connections between the arcing terminal of each coil and the adjacent 0011 exterior to of the adjacent coil extending exterior to the arc chute, a magnetic core for each blowout coil extending through said are chute members and havin a flux-distribution plate at each end thereo and a barrier of arc-resisting material interposed between the said con nections and said flux-distribution lates.

16. A magnetic arc blowout for lnterrupting an electric circuit comprising a series of blowout coils and means whereby said coils are successively included in the circuit of the arc stream as the arc lengthens, said coils having spaces between them whereby the arcs formed between, the arc terminals of adjacent coils will be blown into the spaces and extinguished.

In witness whereof I have hereunto set my hand this 9th day of July, 1926.

OLIVER C. TRAVER.

the arc chute, a magnetic core for each coil extending through said are chute with a fluxdistribution plate at each end hereof, and an arc-resisting barrier interposed between said connections and said flux-distributing plates.

15. A magnetic arc blowoutfor interrupting electric circuits comprising an arc chute formed of arc-resisting members disposed in substantially opposing parallel spaced relation to form a restricted path for the are, a series of spirally-wound blowout coils mounted between said members with a spaoebe- 

